BUG: fix pprinting of singleton tuples GH3291

closes #3291

Author: y-p

pandas/core/common.py

@@ -1806,6 +1806,9 @@ def _pprint_seq(seq, _nest_lvl=0, **kwds):
                                     for e in seq[:nitems])
     if nitems < len(seq):
         body+= ", ..."
+    elif isinstance(seq,tuple) and len(seq) == 1:
+        body += ','
+
     return fmt % body
 
 

pandas/tests/test_common.py

@@ -308,7 +308,7 @@ def test_pprint_thing():
     # escape embedded tabs in string
     # GH #2038
     assert not "\t" in pp_t("a\tb", escape_chars=("\t",))
-
+    assert(pp_t((1,)) == u'(1,)')
 
 class TestTake(unittest.TestCase):